Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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703 FXUS63 KMQT 151148 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 748 AM EDT Sat Jun 15 2024 .KEY MESSAGES... - Dry through today before the return of showers and thunderstorms tonight with next system. - Possible strong to severe thunderstorms Sunday. - Warmer than normal with frequent chances for showers and thunderstorms through next week. && .SHORT TERM /TODAY/... Issued at 406 AM EDT Sat Jun 15 2024 Water vapor imagery/surface analysis early this morning still show Upper Michigan under the influence of high pressure centered over southeast Ontario. So, it has been a quiet night, and the dry stretch will persist through today, yet, before the beginning of a more active period. Currently, skies are clear across the forecast area, which is resulting in some cool lows this morning, especially across the east where ground-based obs are reporting widespread low to mid 40s. Elsewhere, temperatures have been a bit slower to fall over the west and central where 50s are holding steady. Later today, expect the quiet, dry weather to continue as mentioned above with daytime highs topping off in the 60s along the lakeshores and mid to upper 70s inland. Winds will become predominantly southerly at 5 to 15 mph. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 428 AM EDT Sat Jun 15 2024 The pattern becomes increasingly amplified heading into next week as a mid-level trough digging into western North America amplifies a ridge from the Great Lakes through the Atlantic Coast into eastern Canada. This pattern transition will result in much warmer, summerlike weather for Upper Mi by next week. A series of shortwaves riding over the ridge will also bring episodes of showers and t- storms heading into next week with the next best chance likely occurring Sat night into Sunday. Ahead of a more prominent shortwave advancing from the Plains, sfc- 850 mb theta-e advection will strengthen on the nose of a developing 50-60kt LLJ as chances for showers and thunderstorms sneak into the western UP by early evening. PoPs increase from west to east late Saturday night through Sunday morning as the shortwave passes through. Although the timing of the shortwave`s arrival will be less favorable for strong/severe surface-based convection as soundings initially show weak elevated instability, the impressive lift/dynamics (0-6 km shear of 40-50 kts or higher) could still be supportive of stronger storms with gusty winds and small hail especially as one gets into the daytime hours on Sunday and instability increases. Heavy rain will be a threat as well with the stronger t-storms, as PWATs increase to generally 1.5-2 inches. Showers largely end from west to east during the afternoon. Temperatures should increase on Sunday, especially west half where there could be partially clearing in the wake of the passing shortwave. Readings over the west half should increase into the lower to mid 80s in the afternoon and this heat combined with dew points in the 60s will result in muggy and increasingly uncomfortable conditions. To the east, cloudy skies and the round of showers/storms should keep temperatures lower, only peaking in the mid 70s. Warm and unsettled weather will continue into next week. Monday through midweek, the Great Lakes will be situated between high- amplitude ridging over the Eastern Seaboard and deep troughing over the Rockies. Persistent southerly flow into the area will continue to pump in a warm, moist airmass; look for highs Monday and Tuesday to range well into the 80s for most of the area and even a few low 90s readings possible over the interior west half and in the typically warmer southerly downsloping spots. With dewpoints well into the 60s, it will get uncomfortably muggy. Given this unstable airmass and our area situated on the perimeter of the ridge, passing weak waves will leave us with chances for showers and storms both Monday and Tuesday, although mid-level capping from the dome of heat over the area could at the same time keep a lid on some of the convection. With deep layer shear still at 40-50 knots on Monday, any convection that pops that day could have a shot of going severe. Southerly winds will noticeably increase and become gustier on Tuesday as a midlevel shortwave ripples out of the Rockies with a surface low likewise closing off and heading into the Northern Plains, leading to a tightening pressure gradient over the area. Another strengthening LLJ of 40-50 kts may provide the lift needed for some additional convection Tuesday night into Wednesday while the surface low moves through Ontario and sends a frontal boundary across the area. From midweek onward, temperatures will trend more towards normal while the heat dome pattern governing the early part of the week breaks down, although more episodes of convection are possible Wed-Thu as more shortwaves ride along the frontal boundary lingering just to our south. Midlevel flow continues to turn more zonal into next weekend, but weak shortwaves present in model guidance will be enough to keep in chances for showers and daytime thunder to finish out the forecast period. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 745 AM EDT Sat Jun 15 2024 VFR conditions to prevail into tonight at all TAF sites despite increasing cloud cover from west to east throughout the day. As the next system moves closer though, rain and possible thunderstorms will enter the TAF sites starting with IWD around Sun 06Z. Activity will expand into CMX and SAW as well early Sunday morning, resulting in MVFR conditions at all TAF sites by Sun 10Z and possibly IFR at IWD. For now, will not include mention of thunderstorms until confidence increases in timing and coverage. Other impacts include southeasterly surface winds gusting to 24 kts and a LLWS threat at CMX early Sunday morning with an associated low level jet. LLWS will likely need to be added to IWD and SAW as well with future forecast issuances. && .MARINE... Issued at 428 AM EDT Sat Jun 15 2024 Initially tranquil winds this morning will increase out of the SE this afternoon ahead of an approaching shortwave. Expect gusts up to 20 knots in the eastern half of the lake by the late afternoon. Wind gusts increase to 20-25 kts for tonight and Sunday, then winds fall back below 20 kts Monday before increasing out of the SSE again Tuesday with maybe some gusts to 25 knots over the eastern lake. Winds fall back below 20 kts again mid week. Waves should generally be below 3ft for most of the period, but are expected to increase to around 3-5ft across the eastern half of the lake Sunday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...LC AVIATION...TDUD MARINE...LC